Self-Interference Mitigation Using Active Signal Injection for Full-Duplex MIMO-OFDM Systems

This paper presents two self-interference (SI) cancellation methods using active signal injection (ASI) for full-duplex MIMO-OFDM systems. Specifically, the ASI approach considers adding an appropriate cancelling signal to the transmitted signal to reduce the SI at the receiver input to avoid overloading the receiver low-noise amplifier (LNA) and analog-to-digital converter (ADC) while ensuring proper signal detection. In the first method, the cancelling signal uses some reserved subcarriers that are not used for data transmission. In the second method, the constellation points are dynamically extended within the cancellation boundary in order to minimize the SI. The proposed techniques appear to be simple to implement and do not require any change on the receiver structure.